User:Mbennie/Notebook/Papers and Books/IgA Autotransporter

1. Veiga E, de Lorenzo V, and Fernández LA. Autotransporters as scaffolds for novel bacterial adhesins: surface properties of Escherichia coli cells displaying Jun/Fos dimerization domains. J Bacteriol. 2003 Sep;185(18):5585-90. DOI:10.1128/JB.185.18.5585-5590.2003 |

• Fused leucine zipper with autotransporter creating a protein that was expressed on the cell surface and adhered to a similar protein expressed in another population of cells, causing the cells to clump out of solution
• Used IgA as the AT
• Used Fos and Jun as the leucine zippers
• Used an E-tag to test whether the protein was expressed on the surface (using an antibody)
• Used pelB "for an efficient secretion"
• Membrane remains stable

2. Klauser T, Krämer J, Otzelberger K, Pohlner J, and Meyer TF. Characterization of the Neisseria Iga beta-core. The essential unit for outer membrane targeting and extracellular protein secretion. J Mol Biol. 1993 Dec 5;234(3):579-93. DOI:10.1006/jmbi.1993.1613 |

• Concludes a subset of IgA (882 bp) can transport and display a passenger protein by itself, called Iga beta-core
• Figured out that Iga beta was enough, then kept cutting up the protein was no longer functional
• This 227aa protein is very well conserved among Neisseria and Haemophilus
• p. 583 - protein sequence of Iga beta-core
• Suggests that cell express 50,000-100,000 copies
• Iga beta-core is "structurally reminiscent of integral outer membrane proteins (OMPs)"
• Suggests further that forty of the amino acids might not be needed (p. 590)
• "Resembles a typical outer membrane protein with a few additional features"

3. Valls M, Atrian S, de Lorenzo V, and Fernández LA. Engineering a mouse metallothionein on the cell surface of Ralstonia eutropha CH34 for immobilization of heavy metals in soil. Nat Biotechnol. 2000 Jun;18(6):661-5. DOI:10.1038/76516 |

• Describes method of bioremediation using r. eutropha using metallothionein (MT) expressed on the cellular surface using IgA beta
• MT binds heavy metal atoms
• Bioaccumulates about 5% of Cd2+ ions tested, but affects the growth of plants in contaminated soil much more (70%)

4. Klauser T, Pohlner J, and Meyer TF. Extracellular transport of cholera toxin B subunit using Neisseria IgA protease beta-domain: conformation-dependent outer membrane translocation. EMBO J. 1990 Jun;9(6):1991-9. DOI:10.1002/j.1460-2075.1990.tb08327.x |

• Discovery that IgA beta contains the ability to display surface proteins by itself
• Observation that there is a highly conserved region within IgA beta, called IgA beta-core, which is the portion that facilitates outer membrane transport
• Observed that disulphide-dependent folding can cause problems in surface display (protein stuck in periplasm)

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• A basic description of IgA protein in Neisseria gonorrhoeae

6. Veiga E, de Lorenzo V, and Fernández LA. Probing secretion and translocation of a beta-autotransporter using a reporter single-chain Fv as a cognate passenger domain. Mol Microbiol. 1999 Sep;33(6):1232-43. DOI:10.1046/j.1365-2958.1999.01571.x |

• It is possible to have disulfide-dependent folding, but it decreases efficiency (3-fold with Fv)

7. Oomen CJ, van Ulsen P, van Gelder P, Feijen M, Tommassen J, and Gros P. Structure of the translocator domain of a bacterial autotransporter. EMBO J. 2004 Mar 24;23(6):1257-66. DOI:10.1038/sj.emboj.7600148 |

• Resolves crystal structure of N. meningitidis IgA (highly homologous to N. gonorrhoeae IgA)
• "12-stranded beta-barrel with a hydrophilic pore of 10*12.5 A that is filled by an N-terminus alpha-helix"
• Evidence supporting passenger-domain transport, evidence against oligomer of translocater domains
• Alpha-helix has many interactions with interior of hydrophilic barrel: seven salt bridges, sixteen hydrogen bonds, and numerous van der Waals contacts
• Deletion of alpha-helix results in much lower expression of the protein, but increased pore activity